1. Field of the Invention
The present invention relates to compressed-molded preparations in which a composition comprising coated granules of a pharmaceutical component is compressed and molded to give a single dosage form. More particularly, the invention relates to compressed-molded preparations in which there is little breakdown of the coating of coated granules at the time of compressing and molding, and also, to preparations in which the rate of disintegration, and in turn, the release rate of the pharmaceutical component, can be freely controlled or modulated.
2. Description of the Background
It is well known that granules coated with coatings possessing water insoluble, intestinally soluble, acid soluble, or water soluble features can be used in order to obtain granules having sustained-release characteristics, or taste- and smell-masking characteristics. However, when the coated granules are processed to form compressed-molded tablet preparations, the coating of the coated granule is very often destroyed by the pressure which is applied, thus damaging the function of the coatings. Since advanced and sophisticated technologies are needed because of this reason, coated granule preparations are usually marketed as they are or in capsule form.
As a means to solve such problems, a method for preparing tablets which involves using microcrystalline cellulose together with the coated granules has been proposed (Japanese Patent Laid-open No. 221115/1986). However, when a large amount of microcrystalline cellulose is used in the non-coated component, the stability of the active components may be lost or damaged, or the manufacturing procedure of the preparation may become difficult, depending upon the form of the non-coated component, or the active drug ingredient or the compound used for producing the coated granules. Also, because the disintegrability of microcrystalline cellulose is high, it is difficult to control the rate of movement of the coated granules in the alimentary canal, as well as the release rate of the active ingredient from the non-coated component.
In view of such a present situation, the inventors carried out research related to compressed-molding of compositions containing coated granules. As a result of the research, it was discovered that by formulating a non-swelling polymer into the non-coated components, compressed-molded preparations could be obtained which were hard enough for practical use, and yet of which coating applied to the coated granules was resistant to destruction. Also, it was found that the disintegration characteristics of the compressed-molded preparations as well as the release charactertics of the active ingredient could be freely controlled or modulated by controlling the amount of non-swelling polymers to be formulated and also by adding disintegrators, waxes, etc. Such findings have led to the completion of the present invention.